Financial Instruments - Financial Instruments and Balance Sheet Classifications (Detail) - USD ($) $ in Thousands		Jan. 31, 2022	Apr. 30, 2021
Investment Holdings [Line Items]
Cash and cash equivalents		$ 846,505	$ 850,778
Marketable Securities, Current		73,110	63,667
Marketable securities, non-current		187,635	182,692
Income Taxes & Other Receivables		1,491
Fair Value		1,108,741	1,097,125
Other Accrued Liabilities			(12)
Fair Value, Inputs, Level 2
Investment Holdings [Line Items]
Cost		80,308	80,325
Unrealized Gains			1
Unrealized Losses		(205)	(27)
Fair Value		80,103	80,299
Cash and cash equivalents		3,499	9,499
Marketable Securities, Current		61,205	54,583
Marketable securities, non-current		15,399	16,217
Fair Value, Inputs, Level 2 | Commercial Paper
Investment Holdings [Line Items]
Cost		38,857	51,979
Unrealized Gains			1
Unrealized Losses		(34)	(7)
Fair Value		38,823	51,973
Cash and cash equivalents		1,999	9,499
Marketable Securities, Current		36,824	42,474
Fair Value, Inputs, Level 2 | Corporate Notes/Bonds
Investment Holdings [Line Items]
Cost		39,951	26,371
Unrealized Losses		(171)	(20)
Fair Value		39,780	26,351
Marketable Securities, Current		24,381	10,134
Marketable securities, non-current		15,399	16,217
Fair Value, Inputs, Level 2 | U.S. Treasury and Agency Securities
Investment Holdings [Line Items]
Cost		1,500	1,975
Fair Value		1,500	1,975
Cash and cash equivalents		1,500
Marketable Securities, Current			1,975
Fair Value, Inputs, Level 2 | Foreign Exchange Forward Contracts
Investment Holdings [Line Items]
Income Taxes & Other Receivables		1,491
Fair Value		1,491	(12)
Other Accrued Liabilities			(12)
Fair Value, Inputs, Level 1 | Mutual Funds
Investment Holdings [Line Items]
Marketable Securities, Current	[1]	11,905	9,084
Marketable securities, non-current	[1]	172,236	166,475
Fair Value	[1]	184,141	175,559
Fair Value, Inputs, Level 1 | Equity Securities
Investment Holdings [Line Items]
Marketable Securities, Current		11,905	9,084
Marketable securities, non-current		172,236	166,475
Fair Value		184,141	175,559
Fair Value, Inputs, Level 1 | Cash
Investment Holdings [Line Items]
Cash and cash equivalents		754,823	752,737
Fair Value		754,823	752,737
Fair Value, Inputs, Level 1 | Money Market Funds
Investment Holdings [Line Items]
Cash and cash equivalents		88,183	88,542
Fair Value		$ 88,183	$ 88,542

[1] These investments are held in trust for settlement of the Company’s vested obligations of $175.2 million and $157.3 million as of January 31, 2022 and April 30, 2021, respectively, under the ECAP (see Note 6 — Deferred Compensation and Retirement Plans). Unvested obligations under the deferred compensation plans totaled $25.9 million and $26.5 million as of January 31, 2022 and April 30, 2021, respectively. During the three months ended January 31, 2022, the fair value of the investments decreased; therefore, the Company recognized a loss of $7.7 million, which was recorded in other (loss) income, net. During the nine months ended January 31, 2022, the fair value increased; therefore, the Company recognized a gain of $2.4 million, which was recorded in other (loss) income, net. During the three and nine months ended January 31, 2021, the fair value of the investments increased; therefore, the Company recognized a gain of $15.2 million and $27.2 million, respectively, which was recorded in other (loss) income, net.